1. Field of the Invention
The present invention relates to the field of LCD (liquid crystal display) technology, more particularly to a display panel and a display apparatus having the same.
2. Description of the Related Art
Blue phase liquid crystal is a special phase in liquid crystal. When no voltage is applied, the blue phase liquid crystal can be regarded as having an equivalent spherical shape and assume optical isotropy without causing optical path difference in the light passing it; when voltage is applied, the blue phase liquid crystal can be regarded as being stretched into an equivalent particulate shape having a major axis consistent with the electric field and assume optical anisotropy and will cause optical path difference in the light passing it according to birefringence principle (Kerr effect). The blue phase liquid crystal has the following advantages: (1) rapid responsive speed, typically less than 1 ms in response time; thus a color film can be omitted, and a field sequential color control can be realized; (2) it can use electric field to induce birefringence principle directly to realize display without an alignment layer and rubbing treatment; (3) when no voltage is applied, the blue phase liquid crystal assumes isotropy without light leak in a dark state and with a wide viewing angle. Therefore, the blue phase liquid crystal are a kind of liquid crystal display material of good prospect for use.
However, since the light for a display passes through the liquid crystal cell perpendicularly, in order to induce birefringence, the blue phase liquid crystal must be laterally stretched. For that reason, the existing blue phase liquid crystal display apparatus basically uses a lateral electric field in parallel with the display panel to drive the blue phase liquid crystal, such as an in-plane switching (IPS) mode. In this mode, the blue phase liquid crystal is driven and stretched near a pixel electrode and a common electrode in the same plane so as to induce anisotropy. Since the lateral dimensions of the blue phase liquid crystal in the length and width directions are a number of times larger than their dimension in the thickness direction, under the same voltage conditions, the intensity of a lateral electric field (in parallel with the display panel) is a number of times less than the intensity of a perpendicular electric filed (perpendicular to the display panel), and the lateral electric field is not able to penetrate throughout the whole liquid crystal layer. Therefore, the drive by a lateral electric field needs a large driving voltage. The existing blue phase liquid crystal display apparatus involves a problem of having too large a driving voltage. Although a perpendicular electric filed (perpendicular to the display panel) needs a much smaller driving voltage, there is a problem that the perpendicular electric filed is not compatible with the perpendicular light (perpendicular to the display panel).